0-60mph ECO vs. PWR

UH thats what CVT is all about. Please

 

Depends, doesn't it? "Continuously variable." The classic is two cones pointed in opposite directions with a belt between them. What am I missing?

 

wow.... here.. play with this for a while. Prius PSD the "modes" only change throttle input below 50% as others have already posted.. anything over and it's in "normal" mode... it's designed to keep your foot from getting tired. (some like the jackrabbit start, some like to crawl, and some like EV.. so toyota made them into programs)

on the prius.. full throttle is always full throttle. it's not based of the ICE it's based off the programing of the electric motors.

you never see full rpms of the ICE till around 46mph with the PSD... where in a cvt (belt/cone) you can get max rpms from the start. (then the cvt catches up)

 

A normal CVT has a mechanical arrangement that allows for a continuous variation in gear ratios. The most common is the dual cone belt system, but many others exist, such as plate and drive wheel and ball drive systems.

The Prius uses no such mechanical system. All it has is a fixed planetary gear set. The effective gear ratios of the Prius are accomplished by varying the field currents of the two MGs, essentially varying the ratio of power transfered mechanically and electrically. This is why most of us refer to the transmission on the Prius as an eCVT, since all of the magic is electronic.

Tom

 

In Toyotas own website they call it CVT.

"
Hybrid Synergy Drive with CVT
1.8 VVT-I Petrol Engine twinned with a light and compact high output motor that not only provides fuel efficient motoring, but also assists the petrol engine under hard acceleration. The Electric motor and generator in the New Prius are 33% lighter than the previous Prius whilst providing 20% more power.

Transmission

Continuously Variable Transmission (CVT)

"

I don't see them calling it ECVT

The ICE needs spark plugs to power it up you don't call it EICE do you? Of course it uses electic power to shit the ratios of the gears (which btw are made out of metal not electrical particals) and it is a continues shift between the gears.

 

qbee42 is correct.

 

I understand that there are many variations of CVTs other there but it is still a CVT. CONTINOUS VARIABLE!

When you drive your car do you feel gear change? No? Ok good then it is Continous!

And no offense but I already quoted on their own website and they call it CVT.

 

You are wrong, wrong, wrong. Normally I am fairly tolerant of people not understanding the intricacies of the Prius drive system, but I am willing to make an exception in this case. The Prius does *not* shift gears - ever. There are no shiftable metal gears, or plastic ones for that matter. There is no clutch in the conventional sense. There are no brake bands in the transmission. There are no cones. In short there is nothing even remotely similar to a manual, normal automatic, or mechanical CVT.

The Prius is a unique beast. All of the power is transfered through fixed planetary gears and an electrical path from MG1 to MG2, sometimes with a stopover in the HV battery. Nothing shifts. The computers vary the field currents of MG1 and MG2 to accomplish the task of varying the virtual gear ratio. Note that it doesn't change a real gear ratio, just the effective ratio of how much power goes through the electrical path verses how much goes through the mechanical path.

As for the Toyota website, sure, they call it a CVT. It does the same thing as a CVT, but it does it a new and more clever way. Toyota marketing doesn't see any added value in splitting hairs and confusing customers. Most people barely understand the concept of a CVT without throwing in the complexity of HSD. Many of us call it an eCVT because it electronically accomplishes the same task as a CVT. This group is technically way beyond your average Toyota owner.

Tom

 

It is not continuously variable. It is fixed at one gear ratio.

Tom

 

I am talking about the concept of CVT. I keep saying continuous.

Yeah it has one gear ratio but the whole power split device act as a CONTINUOUSLY VARIABLE TRANSMISSION, eliminating the need for a manual or automatic transmission, which is the reason why toyta called it CVT.

They have used this on the gen 1 2 and 3 and they have called it CVT because it acts like one. Continuous regardless whether it has one gear ratio with ring gear and sun gears.

So if they call it CVT why call it otherwise?

 

The only thing in a HSD that is continuously variable is the engine RPM. The main motor (MG2) doesn't have any kind of "transmission" and is always in the same "gear". The planetary power split device allows the ICE to run at a chosen RPM to keep it inside its most efficient mode, almost independent of wheel rotational speed. From the point of view of the ICE, yes there is something between itself and the wheels that seems to act like a continuously variable transmission (hence the marketing term of "CVT" from Toyota, to make it easily understandable). From the point of view of the wheels, there is no clutch and no transmission. The car is always kept in the same "gear".

A quote from [ame="http://en.wikipedia.org/wiki/Hybrid_Synergy_Drive"]Wikipedia's article on the HSD[/ame]:

So, no, there is no [ame="http://en.wikipedia.org/wiki/Continuously_variable_transmission"]CVT[/ame] in a Prius:

 

This is going way to far into symantics, Toyota refers to the car as having a cvt so it has a cvt. That technically it operates differently that other models of cvt, as you pointed out there are many, is neither here or there. It feels like a cvt it's continuous with no physical gear selection, it's variable most definitely between power sources and it sends the power towards the wheels. But ultimately it is a defined term in toyotas literature so that is what it is.

Heck the murano cvt is electronically controlled as well to "give" it gears. So is that no longer a cvt? And look at audi they even combine tiptronic with their version of a cvt in a huge variety of cars. Also a cvt.

Ps. Don't know whether you get those versions in the us as they are only coupled to diesels in Europe.

Anyway regardless if that, whilst in a very detailed technical sense and perhaps even in accordance with the original van doornes transmission patents you are right. The point is cvt is a name used by Toyota. So saying it is not will confuse rather than educate people as in a language technical sense you are wrong ;-)

 

I don't know why we are arguing about this point really.

They call it CVT and thats it. They gave their drive train a name HSD. Acts like a CVT.

If all you arguing is that there are no Variable then why call it EcVt?

It doesn't matter whether it is Electronic or Mechanical CVT it acts like one and so therefore they call it CVT. No E infront.

Actually we should just call it CT

 

Roflmao very true

 

It's called HSD: Hybrid Synergy Drive. The part at the core is the PSD, or Power Split Device. Any other terminology can only be used in comparison, such as saying "It is like a CVT."

Tom

 

Better tell that to Toyota as they clearly state cvt and hsd. And that is the point being argued.

My name is Jean-Paul regardless of the language used nor environment nor anyone thinking they know better than my parents. Not translated to John, Jan, Jean and not eJP ;-) it says so on my birth certificate although to be fair I do listen to Oi git!

 

The point being argued is whether you understand the difference between a conventional CVT and HSD. Toyota is free to call it anything they want. They can call it Bob, but it still isn't a mechanical CVT.

Tom

 

As far as I know, the ECO and PWR mode don't make much of a difference to me. ECO makes the throttle very responsive and almost jumpy, and ECO has less of a reaction time.

 

That's why we don't agree as that is not the point argued by me at all ;-)